SAN FRANCISCO (MarketWatch) — Oil futures drifted lower Monday after the deadline for talks over Iran’s nuclear programs was extended and investors debated whether the Organization of the Petroleum Exporting Countries will move to alleviate a global supply glut by cutting production.

Light, sweet crude for January delivery
US:CLF5
fell 73 cents, or 1%, to settle at $75.78 a barrel on the New York Mercantile Exchange. That put a stop to a two-session winning streak.

ICE January Brent futures
UK:LCOF5
slipped 68 cents, or 0.9%, to end at $79.68 a barrel, also after two sessions of gains.

Talks between Iran and six major powers about curbing Tehran’s nuclear program will be extended to June 30, according to a report from The Wall Street Journal on Monday, citing U.K. Foreign Secretary William Hague. (Read: Talks to curb Iran’s nuclear program extended)

Failure to extend the talks would have heightened worries about instability in the region, potentially triggering a spike higher in oil futures, said Naeem Aslam, analyst at Ava Trade, in emailed comments.

”However, because these talks have been delayed so we are seeing only a minor reaction to this outcome,” he said.

A deal would lift sanctions on Iran’s oil exports, potentially adding to the global supply of oil.

Meanwhile, OPEC ministers are scheduled to meet Thursday in Vienna.

“The rise of the U.S. oil producer has made life very difficult for the old cartel and it is clear that there is no consensus on what to do,” said Phil Flynn, senior market analyst at Price Futures Group in Chicago. “Saudi Arabia seems focused on the long game as it tries to outlast the shale oil production threat from the U.S. The Saudis are ready for a showdown the question is if anyone else is?”

Meanwhile, a return to warmer weather in the U.S. put pressure on natural gas futures, with the December contract
US:NGZ14
plummeting 11 cents or 2.7%, to end at $4.1510 per million British thermal units.

December gasoline
US:RBZ4
lost 2 cents, or 1.1%, to settle at $2.0334 a gallon on Nymex. December heating oil
US:HOZ4
fell less than a penny, or 0.4%, to $2.3955 a gallon, also on Nymex.

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